320
FXUS65 KBYZ 232207
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
407 PM MDT SUN AUG 23 2026
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING. A
FEW STORMS COULD BE STRONG TO SEVERE, WITH STRONG WIND GUSTS
55-65 MPH THE MAIN THREAT. LOCALIZED HEAVY RAINFALL IS ALSO
POSSIBLE.
- DRIER WITH SEASONAL TEMPS NEXT WEEK WITH JUST AN OCCASIONAL
CHANCE OF PRECIPITATION.
UPDATE
SEVERE THUNDERSTORM WATCHES HAS BEEN ISSUED FOR SOUTH CENTRAL AND
SOUTHEAST MT INTO THIS EVENING. THE FORECAST REMAINS ON TRACK. STP
DISCUSSION
THROUGH SATURDAY...
A FILLING UPPER LOW TRACKING THROUGH THE PAC NW WILL CONTINUE TO
SLIDE EAST ALONG THE US CANADA BORDER, WORKING TO BREAK DOWN THE
UPPER RIDGE OVER THE REGION TODAY INTO MONDAY. AN ASSOCIATED COLD
FRONT WILL SWEEP THROUGH THE AREA LATE THIS AFTERNOON AND EVENING.
AREAS GENERALLY WEST OF BILLINGS COULD SEE A PERIOD OF ELEVATED
FIRE WEATHER CONCERNS THIS AFTERNOON AS PRE-FRONTAL CONDITIONS
BRING WESTERLY WIND GUSTS OF 15-30 MPH, WITH HUMIDITY DOWN NEAR 20
PERCENT.
EXPECT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO FORM OUT
AHEAD OF AND WITH THE FRONT, STARTING OVER THE WEST EARLY THIS
AFTERNOON, SPREADING EAST INTO THE EVENING HOURS. CAPE VALUES OF
500-1000 J/KG, 30-40KTS OF 0-6KM SHEAR, AND STEEP LAPSE RATES
SHOULD ALLOW A FEW STRONG TO SEVERE THUNDERSTORMS TO DEVELOP. THE
STORM PREDICTION CENTER HAS ISSUED A RISK LEVEL 2 OF 5 FOR SEVERE
STORMS OVER CENTRAL AND WESTERN AREAS, WITH A MARGINAL RISK
ELSEWHERE. THE MAIN THREAT WITH THESE STORMS IS THE POTENTIAL FOR
WIND GUSTS IN EXCESS OF 70 MPH AND HAIL GREATER THAN 1 INCH. BRIEF
HEAVY RAIN IS ALSO POSSIBLE WITH THUNDERSTORMS.
BEHIND THE FRONT, COOLER AND DRIER CONDITIONS SETTLE INTO THE
AREA FOR MONDAY, WITH TEMPERATURES DOWN INTO THE 80S FOR MOST
LOCATIONS. BREEZY NORTHWEST WINDS OF 15-30 MPH NEAR THE DAKOTAS
BORDER AND AFTERNOON HUMIDITY DOWN INTO THE UPPER TEENS AND 20S
PERCENT WILL BRING LOCALLY ELEVATED FIRE WEATHER CONCERNS. UPPER
LEVEL RIDGING THEN BUILDS IN BY TUESDAY, BUT WEAK ENERGY AND
SLIGHTLY ABOVE NORMAL MOISTURE (PWATS AROUND 110-140% OF NORMAL)
WILL ALLOW FOR PERIODIC CHANCES (10-40% CHANCE) FOR SHOWERS AND
THUNDERSTORMS TO CONTINUE THROUGH THE END OF THE WORK WEEK. HIGHS
ARE FORECAST TO RANGE FROM THE MIDDLE TO UPPER 80S MONDAY AND
TUESDAY. A GRADUAL WARMING TREND IS THEN FORECAST INTO THE SECOND
HALF OF THE WEEK WITH TEMPERATURES IN THE UPPER 80S TO LOWER 90S.
STP
AVIATION
18Z DISCUSSION...
WINDS WILL REMAIN GUSTY (UP TO 25 KTS) OUT OF THE WEST FOR MOST OF
THE REGION (INCLUDING KBIL) THROUGH 06Z TODAY. THE MAIN CONCERN
IS THE DEVELOPMENT OF TS AROUND 20Z OVER THE MOUNTAINS NEAR KLVM
AND THEN THEY PUSH EAST. TEMPO LINES WERE INCLUDED IN KBIL/KLVM
FOR WIND GUSTS WITH THESE STORMS UP TO 50 KTS, ALTHOUGH IT IS NOT
OUT OF THE QUESTION TO SEE A GUST AS HIGH AS 60 KTS WITH THE
STRONGEST STORM TODAY. KSHR AND SE MONTANA HAVE LESS OF A
LIKELIHOOD OF SEEING THESE STORMS OR IMPACTFUL WINDS SO THEY HAVE
PROB30 LINES FOR THESE STORMS. THAT IS ONLY DUE TO THE LOWER
CONFIDENCE / COVERAGE OF THE STORMS AS THEY PROGRESS EASTWARDS, IF
A STORM DOES IMPACT ANY TERMINAL GUSTS OVER 40 KTS ARE POSSIBLE.
OVERNIGHT TONIGHT THERE COULD BE SOME PATCHY FG BUT THERE IS LOW
CONFIDENCE IN THIS. EVEN IF IT WERE TO OCCUR, IT WILL BE VERY
LOCALIZED IN THE FOG PRONE AREAS. MOUNTAINS WILL BE PARTIALLY
OBSCURED THROUGH 08Z. VFR CONDITIONS ARE EXPECTED OUTSIDE OF
CONVECTION. SLANT RANGE VISIBILITY MAY BE SEE MINOR IMPACTS DUE
TO SMOKE. WMR
PRELIMINARY POINT TEMP/POPS
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 095 062/088 060/085 061/090 063/093 064/090 062/089
3/T 30/K 00/U 00/B 11/B 41/B 21/U
LVM 089 049/086 049/084 051/089 052/090 052/088 050/086
6/T 20/K 02/T 22/T 32/T 41/U 21/U
HDN 097 059/088 055/087 056/092 060/095 061/091 059/091
3/T 30/U 00/B 00/U 11/B 21/B 21/U
MLS 096 063/086 058/085 056/087 061/093 064/091 061/089
1/U 20/U 00/U 00/U 01/B 21/B 21/B
4BQ 095 064/087 059/086 057/088 062/092 064/091 062/090
2/T 20/U 00/B 00/U 11/B 21/B 21/B
BHK 093 060/088 053/085 050/086 053/090 057/091 056/089
2/T 20/U 00/U 00/U 01/B 32/T 33/T
SHR 092 057/087 054/084 052/088 055/091 057/089 055/088
3/T 30/U 02/T 11/B 11/B 11/B 21/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...SEVERE THUNDERSTORM WATCH 620 IN EFFECT UNTIL 10 PM MDT THIS
EVENING FOR ZONES 29>33-36-37-57-58-138-139-169-171-173-235.
SEVERE THUNDERSTORM WATCH 617 IN EFFECT UNTIL 7 PM MDT THIS
EVENING FOR ZONES 34-40-42-56-63>68-141-170-172-228.
WY...NONE.
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